I'm a trackball man. I don't know how it happened or when exactly, but if I can avoid a mouse or a touch pad, I will. A lot of what I do for work and fun on a computer is graphics-related. There is nothing more annoying than running out of mouse pad and/or desk space when trying to finish a pen or brush stroke in Adobe Creative Suite, which is part of why I abandoned the mouse altogether.
Thumb- or finger-trackballs are all fine with me. I actually use the Marble® Mouse at work and the TrackMan® Wheel at home, which have two entirely different hand configurations. Nothing terribly fancy, but they serve their purpose.
I have my right hand on the Marble® Mouse for 8-10 hours a day at the TMC office in Norwalk, CT, and never have the wrist problem I used to have while working with a mouse all day. It has an extra large trackball for improved control, minimizing the amount of movement required by my fingers, and requires virtually no wrist involvement whatsoever. That and the Optical Marble® technology add to the precision I need while working in Illustrator and Photoshop, yet giving me the quick freedom I need to juggle 3 different Internet browser windows with uncountable open tabs, thousands of lines of code and files in Dreamweaver, and 50 or so Outlook e-mail windows.
The best part is that the trackball gives all the support and comfort of an orthopedic mouse or mouse pad, without all of the bulk and padding, and unlimited freedom of motion that a mouse can't deliver. I'm sorry, but a fully functional orthopedic mouse is like moving a brick around your desk. Trackballs can be large and give you the support you need while delivering the results you want, because they don't have to move anywhere.
Both of the models I use have a sleek design and simple style, which fits well into most workspaces. If you like to maintain that whole "I'm wireless" image, there are multiple wireless trackball options as well; although I think it's just an added battery cost. The beauty of a trackball is that it has unlimited on screen movement with little-to-no physical movement. Unless you sit 5+ feet away from your computer, there's really no need to go wireless.